From dbd3393c56a8794fe596e7dd20d0efa613b9cf61 Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa <hannes@stressinduktion.org> Date: Tue, 27 Oct 2015 22:40:40 +0100 Subject: [PATCH] ipv4: add defensive check for CHECKSUM_PARTIAL skbs in ip_fragment CHECKSUM_PARTIAL skbs should never arrive in ip_fragment. If we get one of those warn about them once and handle them gracefully by recalculating the checksum. Cc: Eric Dumazet <edumazet@google.com> Cc: Vlad Yasevich <vyasevich@gmail.com> Cc: Benjamin Coddington <bcodding@redhat.com> Cc: Tom Herbert <tom@herbertland.com> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net> --- net/ipv4/ip_output.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 0b024178edd39..4233cbe47052d 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -533,6 +533,11 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, dev = rt->dst.dev; + /* for offloaded checksums cleanup checksum before fragmentation */ + if (skb->ip_summed == CHECKSUM_PARTIAL && + (err = skb_checksum_help(skb))) + goto fail; + /* * Point into the IP datagram header. */ @@ -657,9 +662,6 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, } slow_path: - /* for offloaded checksums cleanup checksum before fragmentation */ - if ((skb->ip_summed == CHECKSUM_PARTIAL) && skb_checksum_help(skb)) - goto fail; iph = ip_hdr(skb); left = skb->len - hlen; /* Space per frame */